A group is a collection of entities consisting of volumes, surfaces, or edges. Each group must contain only one type of entity. Combinations of types (such as volumes and surfaces) are not supported. Groups simplify model setup, particularly when applying the same setting to large numbers of entities. Entities are grouped based on several criteria, including part name, material, mesh size, or boundary condition.

To Create a Group

1. Set the selection mode (Volume, Surface, or Edge) to the entity type to be added to the group.
2. Right click on the Groups branch in the Design Study bar, and select Create new group.
3. Enter a name for the group when prompted.

To group geometric entities (parts, surfaces, edges), leave the Type at its default value of Geometric.

To group parts by Motion (for linked motion): set the Type to Motion.

To Add Entities and Create Groups on the Fly

To Add Entities Graphically

1. Select model entities.
2. To create a group for the selected entities, right click, and select Group_Create Group. Enter a name for the group.
3. To add selected entities to an existing group, right click, and select Group and the name of the group.

To Add Entities from the Design Study Bar

1. Right click on an entity contained in a sub-branch on the Design Study bar. Select Add to existing group.
2. To select multiple entities that have the same setting, expand the setting branch, hold down the Shift or Ctrl keyboard keys, and select them.
3. A menu lists available groups. Select the group from the list.
4. To create a new group, select Create new group. Enter a name for the group.

Example of group creation from the Design Study bar

To Add Parts by Name

1. To add parts to an existing volume-based group, right click on the group name in the Groups branch, and select Add by name.
2. Enter a portion of the name that is common to all parts to be added to the group. (This is case-sensitive.)
3. Check the Regular expression box

Example of group creation by part name

To Add Selected Entities

To add currently selected entities to a group, right click, and select Create group.

In the Add to Group dialog, either create a new group or select an existing group.

Example of group creation of Selected items

To Remove Entities from a Group

In the Design Study bar, expand the Group branch, and right click on the entities to re removed. Select Remove from group.

To Remove Groups

Delete an individual group by right clicking on it in the Group branch, and click Remove group.

Delete all groups by right clicking on the top level Groups branch of the Design Study bar, and selecting Remove all.

To Combine Groups

Combine the contents of groups by right-clicking on a group, and select Add to existing group.

The other groups containing the same entity type are listed. Click one of the groups from the list to add its contents into the current group.

The group that is selected from the pop-out menu is not altered. (Only the group that was right-clicked is modified.)

For example, to add the volumes of Group2 into Group1, right click on Group1, select Add to existing group, and then select Group2 from the list.

Group 1 will then contain all of its original entities plus those in Group2. Note that Group2 will not be changed.

To Select a Group

To select a group, right click in the Graphics window, click Group, and select the group from the list. Only groups containing entities of the current selection mode are shown.

Only groups containing the type of entity of the current selection type are listed.

Select a group by clicking on its entry in the list. When a group is selected, its entities are added to the Selection List.

Individual items can be deselected or additional items added.

Wall Calculator

Groups of surfaces can be selected for use with the Wall Calculator. The group must have existed during the last run (if it did not exist, simply run 0 iterations prior to examining wall results).

In the Wall dialog, select a group of surfaces by clicking the Group Operation button, and selecting the appropriate group. The surfaces in the group will be added to the Selection list, and wall results on those surfaces will be reported when the Calculate button is pressed.

CAD Entity Groups

CAD Entity groups are collections of parts or surfaces, and are created in the CAD system using a dialog installed with the Autodesk® CFD Connection. They provide a convenient way to automate the assignment of settings and the building of the design study. After launching into Autodesk® CFD, CAD Entity groups are added to the scenario, and appear in the Groups branch of the Design Study bar as Autodesk® CFD groups.

CAD Entity Groups are essential to automation:

• The most versatile type of Rule, the Group Rule, associates a Autodesk® CFD setting (such as a boundary condition or material) to objects in a CAD Entity group. Group rules work closely with CAD Entity groups to automatically apply settings when Autodesk® CFD is launched.
• An important part of the Design Study Builder process is to associate entities from the CAD model with Autodesk® CFD settings. By associating each setting in the design study to a CAD Entity group, settings are automatically assigned to CAD entities contained in the group as the design study is launched.

CAD Entity groups = Autodesk® CFD groups

When the model is launched into Autodesk® CFD, CAD Entity Groups and their contents are listed in the Groups branch of the Design Study bar. They behave as traditional groups, and can be modified as necessary.

If entities are added or removed from a CAD Entity group in the CAD model after the model was initially launched into Autodesk® CFD , the group in Autodesk® CFD is automatically updated the next time the model is launched. To disable automatic group updating:

1. Right click on the group name in the Design Study bar.
2. Uncheck Update when launch from CAD.

For more about CAD Entity groups